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B2B charging - 48V to 24V for boat house bank

Hi All

In final stages of cabling our boat and looking for best solution to drop main battery voltage 48V to 24V for house use. Average daily house use around 2.5 kW with potential peaks of 2.6kW possible at times.

Could use three or four Orion-TR 48:24V 380W converters in paralell direct to load but imagine would over stress converters. I think better solution is to install a separate 24v lithium battery bank (around 2.8kw) as a buffer between DC converters and load - and use converters to keep this bank charged. It appears that Victron do not offer 48:24V B2B chargers.

Would three or four Orion DC converters 48V:24V 380W wired in parallel be suitable to manage house loads via the 24V batteries with a suitable BMS to stop and start converters?

It seems that this solution would provide sufficient amps into the 24V batteries but lack any charge stage cycling - maybe not best solution for long term life of batteries.

We are looking at various Victron Smart batteries or Super pack as house bank.

Appreciate your comments or alternative suggestions.


battery charging
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Paul B answered ·

using three or four Orion-TR 48:24V 380W converters in parallel will be fine just work out your max amps at 24 volts and leave some margin and that should work fine . Ill be setting up 10 of these soon all in parallel all set to the same voltage going from a 48 volt bank 60Kw to a 24 volt bus bar, then running all my 24 volt gear off the bus bar, now I would not recommend this for bow thrusters or windlass units, but other general loads should be fine,

now if you also have 24v sheet winchs that from time to time require large amps etc then a lithium 24 volt battery bank as a buffer would be wise and you couls also reduce the number of orions as well, and setting the voltage to around 26 volts for the lithiums as a battery charger should also be fine and I cant see any long term issues. life wise for the lithiums as they dont mind being left at 80% or 90% for long periods of time, But maybe once every few months raise one unit to say 28.8v for a few days so that the lithiums BMS can balance its cells , (best to do this with no other loads on or raise all the units to 28.8. then back to 26v


so its something that is not cut and dried as a answer for you sorry


just my thoughts hope this is of some help

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Cheers Paul

Thanks for your comments. Battery buffer definitely way to go as we have several high draw electric winches. Just have to check charge profile of batteries we go with and tweek Orion to get voltage to best level. I haven't programmed an Orion but guess it has an output voltage setting - just not a smart cycling setting for lithium batteries.